travertine tiling

City pavements built from travertine could alleviate flooding, clean storm water

Image credit: DT

Cities should build pavements out of travertine, a common form of limestone, to reduce urban flooding and remove heavy metal pollutants from local water, according to a new study.

Researchers at Xi’an Jiaotong-Liverpool University (XJTLU ) in Suzhou, southeast China, said that the material could offer a viable and environmentally friendly alternative pavement option to address the global issue of urban flooding.

Travertine is already commonly used for kitchen benchtops and tiling in homes, but new experiments have showed significant potential to reduce storm water runoff and heavy metal pollutants from the water.

“Urban flooding is a significant challenge in many parts of the world and this is likely to increase as we feel the effects of climate change,” said Dr Xiaonan Tang from the Department of Civil Engineering at XJTLU.

“Traditional pavement materials like concrete are not very absorbent, so in heavy rainfall they create a large amount of runoff. In urban areas, this can cause huge problems as the runoff water has nowhere to go – the rivers it enters into can only hold a certain capacity, creating flooding.

“What we tried to achieve with this study is to find an alternative pavement solution that could help us build smarter cities, capable of managing storm water through the materials they are constructed with.

“Our research revealed the benefits of travertine are twofold: it not only reduces flooding, but it also reduces the amount of heavy metals within flood waters.”

Over the past four decades, natural disasters have cost the Asia-Pacific region about $1.3tr, according to UN estimates, with China, the Philippines, Vietnam and Japan worst-hit by typhoons.

As the region’s population becomes more urban and the effects of climate change cause more extreme weather conditions, exposure to flooding is increasing, UN experts say.

Flood-prone cities such as Wuhan, in China, are increasingly testing new innovations to reduce risks. The metropolis has dubbed itself a “sponge city” and turned to water-absorbing asphalt, among other measures.

Travertine is cheaper than both water-absorbing asphalt and concrete and is found in volcanic areas around the world, but it has yet to be tested to determine whether it is strong enough to be used for roads, the researchers said.

“Travertine is a porous material with kind of sponge texture - it has many tiny holes in it - and those holes actually decrease its economic value in the current market,” said Hamidreza Rahimi, the report’s lead author.

“In its holey form, it’s considered waste material, as it needs to be smooth and hole-free when used in domestic building projects,” he said in a statement.

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